noun

• A leading or drawing off of water from a stream or source.
• The act of receiving anything from a source; the act of procuring an effect from a cause, means, or condition, as profits from capital, conclusions or opinions from evidence.
• (genealogy, linguistics) The act of tracing origin or descent.
• (grammar) Forming a new word by changing the base of another word or by adding affixes to it.
• The state or method of being derived; the relation of origin when established or asserted.
• That from which a thing is derived.
• That which is derived; a derivative; a deduction.
• (mathematics) The operation of deducing one function from another according to a fixed definition, referred to as derivation or differentiation; this is the inverse operation to integration.
• (medicine) A drawing of humors or fluids from one part of the body to another, to relieve or lessen a morbid process.